Method and systems for enhancing oil recovery from ethanol production byproducts

Abstract

Methods and related systems efficiently and effectively recover a significant amount of valuable, useable oil from byproducts formed during a dry milling process used for producing ethanol. The method may include forming a concentrate from the byproduct and recovering oil from the concentrate. The step of forming the concentrate may include evaporating the byproduct using a multi-stage evaporator, as well as recovering the oil before the final stage of the evaporator. Further, the step of recovering oil from the concentrate may include using a centrifuge and, in particular, a disk stack centrifuge. Other aspects of the invention include related methods and subsystems for recovering oil.

1. A method of processing thin stillage concentrate created during a dry milling process used for producing ethanol from corn, comprising:
 recovering oil from the thin stillage concentrate 
 and subsequently evaporating the thin stillage concentrate in an evaporator to further reduce a moisture content and form an evaporated thin stillage concentrate, wherein the evaporated thin stillage concentrate has a lower moisture content than the thin stillage concentrate; and 
 mixing the evaporated thin stillage concentrate with distillers wet grains. 
 
     
     
       2. The method of  claim 1 , wherein the recovering step comprises separating the oil from the thin stillage concentrate using a disk stack centrifuge. 
     
     
       3. The method of  claim 2 , wherein the disk stack centrifuge produces suspended solids and the method further includes isolating and mixing the suspended solids with the distillers wet grains. 
     
     
       4. The method of  claim 3 , wherein the disk stack centrifuge produces a syrup, and the method further comprises mixing the syrup and the suspended solids and the distillers wet grains to form a mixture. 
     
     
       5. The method of  claim 3 , further including mixing the evaporated thin stillage concentrate with a mixture; and drying the mixture. 
     
     
       6. The method of  claim 1 , wherein evaporating the thin stillage concentrate comprises removing an additional amount of water from the thin stillage concentrate in a multistage evaporator. 
     
     
       7. The method of  claim 1 , wherein recovering the oil from the thin stillage concentrate comprises introducing the thin stillage concentrate to a disk stack centrifuge prior to a final stage of a multi-stage evaporator. 
     
     
       8. The method of  claim 1 , wherein recovering the oil from the thin stillage concentrate comprises mechanically processing the thin stillage concentrate. 
     
     
       9. The method of  claim 1 , further comprising drying the distiller wet grains and the evaporated thin stillage concentrate to produce dried distillers grains. 
     
     
       10. A method of processing thin stillage created by a dry milling process used for producing ethanol from corn in order to recover oil, comprising:
 evaporating the thin stillage to reduce a moisture content and form a thin stillage concentrate; 
 introducing the thin stillage concentrate to a disk stack centrifuge and separating at least a portion of an oil from the thin stillage concentrate and subsequently 
 evaporating the thin stillage concentrate to further reduce the moisture content of the thin stillage concentrate and form an evaporated thin stillage concentrate; and 
 mixing the evaporated thin stillage concentrate with distillers wet grains. 
 
     
     
       11. The method of  claim 10 , wherein the evaporating the thin stillage comprises using a multi-stage evaporator to form the thin stillage concentrate from the thin stillage and the step of introducing the thin stillage concentrate to the disk stack centrifuge is completed before a final stage of the multi-stage evaporator. 
     
     
       12. The method of  claim 10 , wherein the evaporating the thin stillage or the thin stillage concentrate comprises using an evaporator including at least one scraped surface heat exchanger. 
     
     
       13. A method of processing thin stillage created by a dry milling process used for producing ethanol from corn in order to recover oil, comprising:
 evaporating the thin stillage to reduce a moisture content and form a thin stillage concentrate, wherein the evaporating the thin stillage comprises using a multi-stage evaporator to form the concentrate from the thin stillage; 
 introducing the thin stillage concentrate to a centrifuge and separating oil from the thin stillage concentrate, wherein the step of introducing the concentrate to the centrifuge is completed before a final stage of the multi-stage evaporator; 
 evaporating the thin stillage concentrate to further reduce the moisture content of the thin stillage concentrate and form an evaporated thin stillage concentrate; and 
 mixing the evaporated thin stillage concentrate with the further reduced moisture content with distillers wet grains. 
 
     
     
       14. A method of processing thin stillage created by a dry milling process used for producing ethanol from corn in order to recover oil, comprising:
 evaporating the thin stillage to reduce a moisture content and form a thin stillage concentrate; 
 introducing the thin stillage concentrate to a centrifuge and separating oil from the thin stillage concentrate; 
 evaporating the thin stillage concentrate to further reduce the moisture content of the thin stillage concentrate and form an evaporated thin stillage concentrate, wherein the evaporating the thin stillage and/or the thin stillage concentrate comprises using an evaporator including at least one scraped surface heat exchanger; and 
 mixing the evaporated thin stillage concentrate with the further reduced moisture content with distillers wet grains. 
 
     
     
       15. A method of processing concentrated thin stillage created during a dry milling process used for producing ethanol from corn, comprising:
 recovering oil from the concentrated thin stillage, wherein recovering the oil from the thin stillage concentrate comprises introducing the thin stillage concentrate to a centrifuge prior to a final stage of a multi-stage evaporator; and 
 evaporating the concentrated thin stillage to reduce a moisture content and form an evaporated thin stillage concentrate prior to mixing with distillers wet grains, wherein the evaporated concentrated thin stillage has a lower moisture content than the concentrated thin stillage.